Is the 8-glass-a-day rule an urban legend? Nutrition Diva dives in
I bet you’ve heard it said that you need to drink at least eight glasses of water a day in order to stay properly hydrated. Perhaps you’ve also read that by the time you feel thirsty you’re already in an advanced state of dehydration, or that most of us are chronically dehydrated. Chances are also good that you’ve been told that drinking caffeinated beverages like tea and coffee cause you to lose more fluid than you take in.
What would you say if I told you that all of these widely held truths are little more than urban legends?
I can almost hear your shocked expressions! The dehydration myth has become so firmly entrenched in our collective consciousness that it may indeed come as a surprise to learn that there is very little scientific support for any of these notions.
Tales of the Overhydrated
Now, I have to tell you that opera singers are among the most over-hydrated people on the planet. That’s right: My people were carrying water bottles everywhere we went for decades before the rest of you got on the H2O bandwagon. Like most young singers, I was inculcated into the cult of hydration by my first voice teacher, who explained the danger and heartbreak that would follow if I failed to keep my vocal cords adequately lubricated.
I could picture the tragedy: I’d step out on stage, open my mouth to sing, and nothing but a small plume of dust—or perhaps a tumbleweed or two—would come out of my mouth. Hey, the odds of success as an opera singer are slim enough. I certainly wasn’t going to take any unnecessary chances!
So, I joined the legion of singers neurotically sucking down liter after liter every day. It’s a wonder I ever got through the first act of an opera without having to leave the stage four times for bathroom breaks.
Drinking Water Is a Good Habit
Look, as excesses go, drinking a lot of water isn’t a bad one. It won’t make you fat. It won’t rot your teeth or give you a hang-over. Drinking lots of water can temporarily assuage hunger pangs, which dieters find useful. It can also help prevent kidney stones in those susceptible to them. Drinking more can ease constipation and—ironically—also alleviate water retention.
The body has a fairly efficient mechanism for getting rid of excess water so under normal circumstances it’s hard to get yourself into trouble drinking water—except the kind of trouble that happens when you find yourself in bumper-to-bumper traffic on the interstate, or on stage for Act II of Puccini’s Turandot, and the next bathroom break is at least 50 long minutes away. Ouch.
Still, as a nutritionist, I feel compelled to point out that most people can stay perfectly hydrated on significantly less than eight glasses of water a day.
So who started this notion that nothing less than two liters of water a day will keep us from multiple-organ failure? You have to wonder whether this whole thing was somehow cooked up by the $60 billion bottled water industry, which has somehow figured out a way to take a cheap and widely available commodity and sell it at a mark up of anywhere from 250% to 3000%, creating an environmental disaster of nightmarish proportions in the process.